Priming method and arrangement for fuel feed system



March 5, 1968 R. K. TURNER 3,371,658

PRIMING METHOD AND ARRANGEMENT FOR FUEL FEED SYSTEM Filed March 17, 1966 2 Sheets-Sheet 1 I INVENTOR. {($57 j 55 W4 R0550? A TURNER 16,0 {/5 150 152 155 ,drrop/vay March 5, 1968 R. K. TURNER PRIMING METHOD AND ARRANGEMENT FOR FUEL FEED SYSTEM Filed March 17, 1966 2 Sheets-Sheet 2 INVENTOR. R055 EPA/ER Maw 47 TOP/V5 Y United States Patent 3,371,658 PRlMING METHOD AND ARRANGEMENT FOR FUEL FEED SYSTEM Robert K. Turner, Toledo, Ohio, assignor to The Tillotson Manufacturing Company, Toledo, Ohio, a corporation of Ohio Filed Mar. 17, 1966, Ser. No. 535,203 11 Claims. (Cl. 123-1875) ABSTRACT OF THE DISCLOSURE This invention relates to a priming method and arrangement for an aspirated type of diaphragm carburetor wherein the diaphragm controls a fuel inlet valve and an actuable member is provided to move the diaphragm to open the inlet valve and a manual priming pump actuated to purge the fuel line of air and fill the fuel chamber with fuel from a supply and establish fuel pressure in the fuel chamber sutficient to release the member from engagement with the diaphragm.

This invention relates to a priming method and arrangement for a fuel feed system especially of the character for supplying liquid fuel and air mixture to an internal combustion engine and more particularly to a priming arrangement associated with a fuel feed system embodying a diaphragm type carburetor or charge forming apparatus wherein the regulation or metering of fuel into the mixing passage of the carburetor or charge forming apparatus is controlled by engine aspiration or reduced pressure in the mixing passage.

The invention has particular utility with fuel feed systems of internal combustion engines of the character employed for marine or outboard installations, stationary engines and engines for powering small vehicles or the like where the fuel tank is disposed below the carburetor or charge forming apparatus and wherein priming is usually necessary in order to initiate the operation of the internal combustion engine.

Priming devices have been employed with charge forming apparatus for outboard marine engines particularly of the two cycle type embodying so-called float-type carburetors wherein the fuel level in a vented bowl of the carburetor is regulated by a float-controlled inlet valve. One form of priming arrangement has been used with a diaphragm type carburetor by employing a vent means externally of the carburetor for purging the fuel feed lines of air in .order to facilitate starting of the engine, an arrangement of this character being disclosed in Phillips Patent 3,177,920. In such vented fuel feed priming systems, some fuel is lost during the priming operation as the operator can only determine by overflow of fuel through the vent tube to the atmosphere when the system has been purged of air. The venting or extrusion of fuel to the atmosphere during such a priming operation involves a fire hazard as well as the loss of fuel attendant each priming operation. An aspirated type of diaphragm carburetor embodies a fuel inlet valve which is normally held in closed position by a spring. The fuel chamber of an aspirated diaphragm carburetor is unvented and it is diflicult or sometimes impossible to develop suflicient pressure upon a manual squeeze bulb priming pump to overcome the pressure of the inlet valve spring to effect fuel flow into the fuel chamber of the carburetor to initiate operation of the engine.

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The present invention embraces a method, arrangement or system associated with an aspirated diaphragm carburetor or charge forming apparatus and a fuel pump arrangement whereby entrapped air in the fuel feed lines or tubes is vented into the carburetor mixing passage through the fuel inlet valve to facilitate easy starting of the engine with which the carburetor is used.

Another object of the invention resides in an aspirated diaphragm carburetor and fuel feed system embodying an arrangement for relieving closing pressure on the inlet valve of the carburetor to enable the venting of the fuel supply line through the carburetor thereby preventing loss of fuel during a priming operation in initiating starting the internal combustion engine.

Another object of the invention is the provision of a method of priming a diaphragm type carburetor for engine starting purposes wherein priming is effected without loss of fuel to the atmosphere whereby potential fire hazard is substantially eliminated.

Another object of the invention resides in a priming arrangement for an aspirated type diaphragm carburetor wherein a diaphragm controlled fuel inlet valve normally spring biased toward closed position is relieved of spring pressure enabling a squeeze bulb primer to be readily manipulated to purge the fuel supply line of air through the inlet valve of the carburetor and when fuel delivered by the squeeze bulb primer fills the fuel chamber and exerts pressure on the diaphragm to close the inlet valve, the operator is apprised by increased resistance encountered in manipulating the squeeze bulb that the priming operation is completed.

Another object of the invention resides in a fuel priming arrangement for an aspirated type diaphragm carburetor wherein the fuel inlet valve of the carburetor is controlled by a movable diaphragm subject to engine aspiration in association with spring means normally urging the inlet valve to closed position, the arrangement embodying means for moving the diaphragm to a position effecting opening of the inlet valve to facilitate fuel delivery into the fuel chamber, which means is automatically restored to its ineffective position by fuel pressure when the fuel chamber is filled and thereby facilitating easy starting of the engine with which the carburetor is used.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a semidiagrammatic illustration of an outboard type of marine engine and diaphragm carburetor and a priming arrangement of the invention associated therewith;

FIGURE 2 is a longitudinal sectional view of a carburetor or charge forming apparatus illustrating one form of fuel inlet valve releasing means forming a component of the priming arrangement of the invention;

FIGURE 3 is a transverse sectional view through the carburetor shown in FIGURE 2;

FIGURE 4 is an enlarged schematic sectional view through the carburetor illustrating a manually operated diaphragm actuator for relieving pressure normally closing the fuel inlet valve;

FIGURE 5 illustrates an electrically energizable means for actuating the diaphragm to relieve pressure normally closing the fuel inlet valve;

FIGURE 6 is a fragmentary sectional view illustrating a modified arrangement of fuel inlet valve in association with a diaphragm actuator for relieving pressure normally closing the fuel inlet valve;

FIGURE 7 is a sectional view through a portion of a diaphragm type carburetor illustrating a modified form of diaphragm actuator for relieving pressure normally closing the fuel inlet valve;

FIGURE 8 is an enlarged fragmentary sectional view of a portion of the construction shown in FIGURE 7, and

FIGURE 9 is an isometric view of a spring detent forming a component of the construction shown in FIG- URES 7 and 8.

While the priming method, arrangement or system of the invention has particular utility with diaphragm carburetors for supplying fuel and air mixture to two cycle or four cycle marine engines of the outboard type, it is to be understood that the invention may be utilized with diaphragm carburetors for supplying fuel to internal combustion engines for other uses where priming means is essential or desirable for engine starting purposes.

Referring to FIGURE 1 of the drawings, there is illustrated in semidiagrammatic form an arrangement or system utilizing an aspirated-type diaphragm carburetor and fuel delivery arrangement for feeding fuel and air mixture to an internal combustion engine for the outboard marine type where the fuel supply tank is disposed beneath the level of the carburetor requiring fuel pumping means to deliver fuel from the tank to the carburetor.

In FIGURE 1 there is illustrated an internal combustion engine 10 of the two cycle type which is inclusive of a crankcase 12, a cylinder 14 secured to the crankcase, provided with a spark plug 16 for igniting the charge in the cylinder. A crankshaft 18 of conventional construction is journaled in the crankcase, the engine being provided with a piston and connecting rod (not shown). The engine crankshaft 18 is equipped with a flywheel 20 and a pulley (not shown), the latter provided with a cable 22 associated with the pulley for manually starting the engine in a Well known manner.

A hollow strut 24 carried by the crankcase 12 depends therefrom and encloses an extension of the crankshaft for transmitting power to a propeller (not shown) provided at the lower end of the strut 24. A sheet metal housing 28 encloses the engine and associated components. The crankcase 12 is fashioned with a boss 30 which mounts the charge forming apparatus or diaphragm carburetor 32, a flange 34 on the carburetor mating with the boss 30, the carburetor being secured to the crankcase by bolts 36, one of which is shown in FIGURE 1.

In the arrangement shown in FIGURE 1, a fuel pump 40 is secured to the crankcase 12 by screws 42, the pump being preferably of the diaphragm type in which the diaphragm is actuated by varying fluid pressure in the crankcase 12 of the two cycle engine 10. A diaphragm pump of the character shown in Phillips Patent 2,796,838 may be employed for the purpose. A flexible tube or pipe 44 connects the outlet 46 of the fuel pump with a fitting 46 at the entrance of an inlet duct 48 in the carburetor body.

A fuel tank or fuel supply receptacle 50 is disposed below the carburetor 32 and is connected with an inlet fitting 52 on the fuel pump by tubular means or tubes 54 and 56 and a priming pump 58, the latter being of flexible squeeze bulb type connected with the tubes 54 and 56 as shown in FIGURE 1. The priming pump means or squeeze bulb 58 is of conventional construction provided with inlet and outlet check valves 60 and 62. When squeeze pressure is applied to the bulb 58, liquid fuel from the receptacle is delivered through the fuel pump 4 40 and into the carburetor through the tube 44 under conditions hereinafter described.

A manually operated vent valve 64 is provided for venting the fuel tank during engine operation, the valve 64 being manually rotatable to a closed position when the engine is not in operation.

The carburetor shown in FIGURES 1 through 3 and illustrated in a schematic or expanded section in FIG- URE 4 is of the aspirated type, that is, a diaphragm type carburetor having an unvented fuel chamber and wherein the diaphragm is influenced by aspiration or reduced pressure in the mixing passage of the carburetor established by engine operation. The carburetor 32 is inclusive of a body 68 provided with a mixing passage 70 having an air inlet region 72, a venturi 74 and a mixture outlet 76, the latter registering with a passage in the boss 30 on the engine crankcase 12, the passage being provided with the conventional reed valve construction employed in a two cycle engine.

A shaft 78 journaled in openings in the body 68 extends across the air inlet region 72 and is equipped with a conventional disc-type choke valve 80 employed for restricting the air inlet 72 during engine starting operations. The choke shaft 78 is equipped with a manipulating arm 82. A shaft 84 journaled in bores in the body 68 extends across the mixture outlet passage 76 and is equipped with a disc-type throttle valve 86 of conventional construction for controlling delivery of fuel and air mixture into the crankcase of the engine. The throttle shaft 84 is equipped with a manipulating arm 88 for controlling the position of the throttle valve 86.

The carburetor body 68 is formed with a generally circular wall portion 90, the planar face of which forms a seat for an annular gasket 91.

A diaphragm 92 of flexible impervious material, such as a nylon fabric impregnated or coated with a synthetic rubber-like material or resin, is disposed with its peripheral region contiguous with the gasket 91 and extends across the region defined by the wall portion 91 which forms a fuel chamber or recess 94. As shown in FIG- URES 2, 3 and 4, the flexible diaphragm 92 forms a wall of the fuel chamber 94.

The fuel chamber 94 is unvented and is in communication with the mixing passage through fuel delivery orifices hereinafter described. The fuel chamber 94 is comparatively shallow to minimize the distance between the diaphragm 92 and the mixing passage 70 to provide a minimum of fuel head on the diaphragm. A cover member or closure plate 96 has a peripheral portion 98 contiguous with the periphery of the diaphragm 92. The gasket 91, diaphragm 92 and the closure member 96 are fashioned with aligned openings accommodating securing screws 100 threaded into openings in the carburetor body 68 for securing these components in assembled relation.

The closure 96 is recessed to provide a space or air chamber 102 to accommodate flexing movements of the diaphragm 92. The air chamber 102 is vented to the atmosphere through a vent opening 104 as shown in FIGURE 3. The diaphragm 92, under the influence of varying pressures or aspiration in the fuel chamber 94, is arranged to control a fuel inlet valve to regulate fuel flow into the fuel chamber 94 for delivery through orifices into the mixing passage 70.

Threaded into a bore in the carburetor body 68 is a valve guide member or sleeve 106 in which is slidably disposed a valve member or valve body 108 having a tapered or needle valve portion 110 which cooperates with an annular valve seat 112, these components being illustrated in FIGURES 3 and 4. The valve body 108 is of polygonal cross section, for example, square cross scction, to facilitate fuel flow along the valve body into the fuel chamber 94. Disposed in the fuel chamber 94 and fulcrumed upon a pin 114 is a lever or motion transmitting member or means 116.

The long arm 117 of the lever is adapted for engagement with a member 118 mounted on the diaphragm 92, the short arm 120 of the lever having operative engagement with the valve body 108. A coil spring 122 has one end seating in a recess in the body 68, as shown in FIG- URE 3, the opposite end of the spring engaging the long arm 117 of the lever 116, the pressure of the spring urging the lever 116 for pivotal movement about its fulcrum pin 114 in a clockwise direction as viewed in FIGURE 3 to normally bias or urge the inlet valve 110 toward closed position or seating engagement with the ported valve seal 112.

The end region of the long arm 117 of the lever is preferably bifurcated or provided with an open ended slot, the furcations straddling a tenon 124 terminating in a head portion 125 providing an articulate connection between the diaphragm button 118 and the lever.

The short arm 120 of the lever may also be bifurcated, the furcations straddling a tenon 127 formed on the valve body 88, the lower end of the tenon terminating in a head portion 128 establishing an articulate connection between the lever 116 and the inlet valve body 108.

Disposed at each side of the diaphragm 92 are disclike members or washers 130 and 132 of metal or other substantially rigid material for reinforcing the diaphragm, the button 118 having a shank portion 119 extending through aligned openings in the reinforcing discs and diaphragm for securing these components in assembled relation.

The carburetor is provided with primary and secondary fuel delivery systems including orifice means for high speed engine operation and for low speed and engine idling purposes. With reference to FIGURES 2 and 4, a main fuel discharge tube 134 opens into the choke band or restricted region of the Venturi 74 providing a main orifice 135. The lower end of a bore 136 in the body 68 below the tube 134 is closed by a plug 137. Formed adjacent the air inlet end of the carburetor is a channel 140 in which is disposed a valve body 141 having a threaded portion engaging a threaded region of a channel 140 whereby the position of the valve body 141 may be adjusted.

A fuel passage 142 connects the channel 140 with the fuel chamber 94. A restricted passage 144 is disposed between the bore 136 and the channel 140. The valve member 141 is provided with a needle valve portion 146 extending into the restriction 144. A fine mesh screen 138 is disposed at the entrance of the main orifice delivery tube 134 to provide a capillary seal to prevent back bleeding of air through the main orifice 135 when the secondary orifice system is delivering fuel into the mixing passage.

The needle valve 146 regulates or meters fuel flow from the chamber 94 to the main orifice 135 provided by the tube 134. The valve body 141 is provided with a knurled head 148 for manipulating the valve.

A sealing gasket 150 surrounds the valve body 141, and a coil spring 152 interposed between the head 148 and the sealing gasket 150 provides friction for holding the valve in an adjusted position. The valve 146 provides fuel adjustment for normal and high speed engine operation.

The secondary fuel delivery system for low speed and engine idling purposes is inclusive of a supplemental chamber 154, a low speed orifice 156 and 'an engine idling orifice 158 opening into the mixing passage in the region of the throttle valve 86, as shown in FIGURES 2 and 4.

As particularly shown in FIGURES 3 and 4, the body 68 is fashioned with a 11mm or channel 160 which is in communication with the supplemental chamber 154 through a duct 162. The bore or channel 160 is in communication with the fuel chamber 94 by a passage 164 and a re stricted passage 166.

Disposed in the bore 160 is a valve body 168 having a threaded portion cooperating with a threaded portion of the bore 160. The valve body 168 is fashioned with a needle valve portion 170 which extends into and cooperates with the restriction 166 for regulating, metering or controlling the delivery of fuel into the supplemental chamber 154 for discharge into the mixing passage through one or 'both orifices 156 and 158 of the secondary fuel delivery system. The valve body 168 is provided with a knurled head 172 for manipulating the needle valve 170.

A sealing gasket 174 surrounds the valve body 168, and an expansive coil spring 176 disposed between the head 172 and the gasket 174 provides sufiicient friction to hold the valve body 168 in adjusted position. The needle valve 170 provides adjustment for engine idling and low speed operation. A stop means (not shown) of conventional construction is associated with the throttle shaft 84 for adjusting the engine idling position of the throttle valve 86 in a conventional manner.

The invention is inclusive of a novel method and means for purging the fuel supply lines or tubes of air in order to effect delivery of fuel from a supply into the carburetor for delivery into the mixing passage to facilitate easy starting of the engine with which the carburetor is used. In the arrangement of the invention the purging of the fuel lines or tubes of air is effected internally of the carburetor by moving the diaphragm to disengage the inlet valve 110 from its valve seat to vent air in the fuel lines through the inlet port of the carburetor.

Means is provided for actuating or flexing the diaphragm in a direction to overcome the pressure of the spring 122 and open the inlet valve 110. The diaphragm closure plate 96 is fashioned with a centrally disposed boss portion 180 fashioned with a bore 182 in which is slidably disposed a diaphragm actuating means which, in the form shown in FIGURES 2 through 4, is a plunger or member 184 having a head or disc-like portion 186 disposed within the air or dry chamber 102 between the diaphragm 92 and the closure plate 96.

The plate 96 is formed with a second boss portion 188 provided with a bore 190 inwhich is slidably disposed a member or detent 192, one end of which frictionally engages a cylindrical wall of the plunger 184. Disposed in the bore 190 is an expansive coil spring 194 biasing or urging the detent 192 into engagement with the pin or plunger 184. The bore 190 has a threaded wall portion accommodating a threaded plug 196 which engages the other end of the spring and maintains the spring under compression to provide a biasing force elfective on the detent or plunger 192.

The diaphragm actuating means or plunger 184 is adapted to be manually pushed upwardly to project a portion of the plunger into the chamber 102 by the operator exerting upward pressure upon the lower end of the plunger 184. Upward movement of the plunger engages the head 186 thereof with the diaphragm button or member 118 and flexes the diaphragm upwardly, swinging or pivoting the lever 116 in a counterclockwise direction about its fulcrum 114, as viewed in FIGURES 3 and 4, compressing the spring 122 and opening the fuel inlet valve 110 to facilitate purging the fuel lines of air and admit fuel past the fuel inlet valve.

Sufiicient biasing pressure is exerted by the spring 194 on the detent or member 192 to overcome the pressure of the lever-biasing spring 122 so as to maintain the diaphragm 92 in an uppermost position of flexure to which it is moved by upward movement of the plunger 184 so that the inlet valve 110 will be held open by the frictional force of the detent 192 against the plunger 184.

In the arrangement shown in FIGURE 1, the sheet metal housing 28 embraces the carburetor .and a supplemental means accessible exteriorly of the housing may be employed to actuate the plunger 184 to elevate the diaphragm 92. As shown in FIGURE 1, a member or lever 200 pivoted upon a pin or fulcrum 202 supported by means (not shown) has an arm 203 adjacent the end of the plunger 184, the other arm 204 extending through an opening 206 in the housing 28 provides a means for actuating or elevating the plunger 184.

The operation of the priming arrangement shown in FIGURES 1 through 4, in starting the engine with which the carburetor is used is as follows: Thefuel lines or tubes 44, 54 and 56 connecting the carburetor and the fuel pump and connecting the fuel. pump and the fuel tank 56 may contain air making it difficult, if not impossible, to develop sufiicient reduced pressure or aspiration in the carburetor mixing passage by manual rotation of the engine crankshaft to lift fuel from the tank 50 to start the engine.

In using the priming method and arrangement of the invention, the operator moves the lever 200, shown in FIGURE 1, in a counterclockwise direction to engage the lever arm 203 with the member or plunger 184 to elevate the plunger. Upward movement of the plunger engages the head 186 thereof with the member 119 at the central region of the diaphragm and flexes the diaphragm upwardly.

The upward flexure or movement of the diaphragm pivots or swings the lever 116 in a counterclockwise direction as viewed in FIGURES 3 and 4, overcoming the biasing pressure of the spring 122 and opening the valve 110.

The detent or retaining member 192, being under pressure of the expansive spring 194, establishes sufficient friction between member 192 and the plunger 184 to hold the plunger 184 in its uppermost or valve-opening position. It is to be understood that the spring 194 is calibrated to exert sufiicient pressure on the detent 192 whereby the friction between the detent and the member 184 is adequate to hold the spring 122 in compressed condition with the fuel inlet valve 110 in open position.

The operator then exerts repeated squeeze pressure on the flexible squeeze bulb primer or priming pump 58 to pump or elevate fuel through the tubes 54, 56, 44 and through the fuel pump to the region of the inlet valve. As the inlet valve 110 is in open position, any air in the fuel conveying tubes is first exhausted through the inlet valve followed by flow of liquid fuel past the valve 110 into the fuel chamber 94. The chamber 94 is rapidly filled with fuel and the air therein exhausted or vented from the fuel chamber through the fuel channels of the primary system past the valve 146 and through the main orifice 135 into the mixing passage, and through the fuel channels of the secondary system past the valve 170 into the mixing passage through the secondary orifices 156 and 158.

The air in the chamber 94 readily flows through these orifices into the mixing passage to purge the chamber 94 and the fuel supply lines of air. When the fuel chamber 94 is filled with liquid fuel, the resistance to flow of liquid fuel past the metering valves 146 and 170 of the carburetor becomes substantial and fuel pressure buils up in the chamber 94 acting against the diaphragm 92.

As the area of the diaphragm 92 is substantial, the fuel pressure built up in chamber 94 overcomes the frictional force of the detent 192 maintaining the plunger 184 in elevated position. The diaphragm 92, under the fuel pressure, is flexed downwardly and moves or returns the plunger 184 to its initial position shown in FIGURES 2 through 4. During downward flexure or movement of the diaphragm 92, the lever 116 is pivoted in a clockwise direction as viewed in FIGURES 3 and 4 assisted by the pressure of the spring 122, which movement closes the inlet valve 110.

The closing of the inlet valve 110 sets up substantial resistance to squeeze pressure on the priming squeeze bulb or pump 58, indicating to the operator that the fuel lines are filled with liquid fuel, that the chamber 94 is filled with liquid fuel and that the fuel chamber and fuel lines have been purged of air vented into the mixing passage. The operator then manipulates the engine starting cable 22 to effect starting of the engine in the usual manner.

Thereafter during normal carburetor and engine operation, the spring biased detent 192 frictionally retains the plunger 184 in its out-of-use position as shown in FIG- URES 2, 3 and 4. Through the method and arrangement of purging or venting the fuel lines and fuel chamber of air into the mixing passage of the carburetor, there is no loss or waste of fuel as the operator is immediately informed by increased resistance to squeeze bulb pressure that the inlet valve has been closed and the system purged of air.

FIGURE 5 illustrates power means for actuating the plunger to elevate the diaphragm and open the fuel inlet valve 110 during a priming operation. The carburetor and diaphragm actuating plunger arrangement of FIGURE 5 is the same as illustrated in FIGURES 2 through 4. The carburetor body 68' is equipped with a metering diaphragm 92 and a closure plate 96' configured to provide an air chamber beneath the diaphragm to accommodate flexing of the diaphragm. The cover 96 is fashioned with a boss in which is slidably disposed the diaphragm actuator or plunger 184' of the construction shown in FIGURES 2 through 4.

The cover 96' is fashioned with a hollow boss 188' accommodating a spring biased detent of the character shown in FIGURES 2 through 4, the detent-engaging spring being held in compression by the screw 196. The arrangement is provided with a sheet metal enclosure 28' of the character shown in FIGURE 1.

Disposed adjacent and beneath the plunger 184 is a member or lever 210 pivotally mounted or fulcrumed upon a pivot pin 212, the pin being mounted upon a suitable support (not shown).

The distal end region 214 of the lever extends upwardly and terminates adjacent to or in contact with the lower end of the plunger 184'. Supported by suitable means (not shown) is a solenoid 216 of conventional construction which is inclusive of a coil 218 and a movable core 220, a projection or tenon 222 of the core being pivotally connected by a pin 224 with the lever 210. A circuit for the solenoid is schematically illustrated including a source of direct current, such as a battery 226, connected with the coil 218 and to a usual ground connection 228 which may be the housing 28 or other metal part of the engine.

The solenoid circuit includes a normally open switch 230, biased to open position by a spring 232. The core 220 is in a normal out-of-center position with respect to the coil 218 as shown in FIGURE 5. The arrangement shown in FIGURE 5 is employed with the carburetor, fuel pump and fuel line system and squeeze bulb primer of the character shown in FIGURE 1.

In the use of the arrangement shown in FIGURE 5, the operator manually closes the switch 230 which completes the circuit through the solenoid coil 218 energizing the coil to effect upward movement of the core 220 into the central region of the coil.

Upward movement of the solenoid core 220 swings the lever 210 about its fulcrum 212, the portion 214 of the lever engaging and moving the plunger 184' upwardly to engage and move the metering diaphragm 92 in the carburetor upwardly to open the fuel inlet valve in the carburetor.

The operator then manipulates the squeeze bulb 58, shown in FIGURE 1, and purges the fuel lines and the carburetor fuel chamber of air in the manner hereinabove described.

The switch 230 is closed only momentarily by the operator to effect upward movement of the plunger 184 through the media of the solenoid 216 and the lever 210, the plunger 184 being held in its diaphragm engaging position by a spring biased detent of the character shown in FIGURE 4. The spring 232 automatically opens the switch 230 when the operator releases closing pressure on the switch.

FIGURE 6 illustrates the diaphragm actuator arrangement in combination with a modified form of fuel inlet valve for the carburetor. The carburetor body 238 is generally of the character of the carburetor body 68 shown in FIGURES 2 and 3, the body having a mixing passage 70" of the same shape as the mixing passage 70 shown in FIGURE 2. The carburetor is provided with a fuel chamber 94", a metering diaphragm 92" and a cover plate 96" for the diaphragm, the cover plate being of the character shown in FIGURE 2.

The cover plate is provided with a vent opening 104" to the atmosphere to equalize the pressure in the air chamber 102 between the cover 96 and the diaphragm 92". The cover plate 96" is fashioned with a depending hollow boss 180 in which is slidably mounted a plunger or member 184" having a head portion 186". The diaphragm 92 is equipped with reinforcing discs '130 and 132" disposed at opposite sides of the diaphragm and secured thereto by a rivet 240.

The cover plate 96" is fashioned with a boss portion 188" provided with a bore 190" accommodating a slidable member or detent 192" biased toward the plunger 184" by an expansive spring 194", an abutment screw 196" threaded into the bore 190" maintains the spring under compression. The friction established at the region of contact of the detent 192" with the plunger 194" is suflicient to maintain the diaphragm 92 in its uppermost position during priming operations.

In this form of construction the carburetor body 238 is equipped with an inlet nipple or fitting 46" adapted to be connected with the fuel pump by a flexible tube, such as the tube 44 shown in FIGURE 1. The central region of the carburetor body 238 is fashioned with a bore 242, the axis of which is aligned with the center of the diaphragm 92". A counterbore in the carburetor body is threaded as at 244 to accommodate a fitting 246. The fitting 246 is provided with a ledge forming an abutment positioning an annular valve seat 248 in a bore 250 in the fitting 246.

A sealing gasket 252 is provided between the fitting 246 and the ledge provided at the entrance of the bore 242. Slidably disposed within the bore 250 and above the annular valve seat 248 is a valve body 254 bored to accommodate an expansive coil spring 256. The valve body 254 is fashioned with a needle valve portion 258 providing an inlet valve adapted to seat in the annular valve seat 248 as shown. The valve body 254 is provided with a depending stem or projection 260 which terminates adjacent the rivet 240 with the diaphragm in its normal or neutral position.

The inlet fitting 46" is fitted into a bore 262 in the carburetor body and the bore 262 is in communication with the bore 242 by a duct, passage or channel 264 partially encircling the mixing passage 70" to conduct fuel from the fuel pump or supply through the inlet fitting 46" to the region of the inlet valve 258. When the diaphragm 92' is in neutral position, that is, when it is not influenced by aspiration in the mixing passage, the inlet valve 258 is closed and the terminus of the stern 260 is adjacent the upper surface of the rivet 240.

When the diaphragm is subjected to engine aspiration in the mixing passage, the diaphragm is flexed upwardly and opens the valve 258 to admit fuel into the fuel chamber 94". The spring 256 exerts only minimum pressure sufiicient to bias the inlet valve 258 to closed position, the minimum biasing pressure being readily overcome by upward movement of the diaphragm 92" when the latter is subjected to engine aspiration.

The arrangement shown in FIGURE 6 is manipulated in the same manner as the arrangement shown in FIG- URES 2 through 4 in priming the engine. The operator first moves the plunger 184" upwardly engaging the head 186" thereof against the rivet 240 flexing the diaphragm upwardly, concomitantly moving the plunger 260 and the inlet valve 258 upwardly to open the valve for purging the fuel lines of air and admit fuel into the chamber 94".

A squeeze bulb priming member 58 (shown inFIG- URE l is actuated by the operator to effect fuel delivery from a supply tank through the fuel pump to the chamber 94" until the chamber is filled with fuel and the diaphragm 92" flexed downwardly by the fuel pressure to effect a closing of the inlet valve 258, completing the priming operation.

FIGURES 7 through 9 illustrate a modified arrangement of spring means and diaphragm actuating plunger for elevating the diaphragm and opening the fuel inlet valve of the carburetor during priming operations. The carburetor body 68a is equipped with a metering diaphragm 92a of the character shown in FIGURES 2 and 3, the diaphragm being reinforced by discs 130a and 132a, the discs and diaphragm being held in assembled relation by a rivet operatively engaged with an inlet valve operating lever 117a which controls a fuel inlet valve for the carburetor in the manner shown in FIGURE 3.

The diaphragm 92a is enclosed by a cover plate 268, screws a securing the plate 268 and diaphragm 92a in assembled relation with the carburetor body 68a. The cover plate 268 is shaped to provide an air chamber 102a to accommodate flexing movements of the diaphragm. The central region of the plate 268 is fashioned with a depending boss 270 bored to slidably accommodate a diaphragm actuator or plunger 272, the plunger having a head portion 274 for engagement with the rivet 118a at the central region of the diaphragm.

The plunger 272 is fashioned with two spaced circumferential grooves or recesses 276 and 278 as particularly shown in FIGURE 8. Disposed adjacent and contiguous with the upper surface 280 is a hairpin-like member 282 of spring wire having semicircular loop portions 284 straddling the plunger 272 and of a dimension to selectively and resiliently engage in the circumferential grooves 276 and 278 shown in FIGURE 8. The plate'268 is provided with a bore 286 accommodating a hollow rivet 288, the central opening'290 in the rivet providing a vent opening for the air chamber 102a.

The bore 286 in the plate 268 is in registration with a closed loop 292 provided at the return bend at one end of the hairpin spring 282. The head 294 of the hollow or tubular rivet is of large area to embrace the portion of the spring member adjacent the loop 292 in order to secure the spring member 282 in contiguous engaging relation with the upper surface 280 of the plate 268.

As shown in FIGURE 8, the intermediate semicircular portions 284 of the spring member 282 are engaged in or form detents extending into the upper circumferential recess 276 in the plunger 272 to normally maintain the plunger 272 out of engagement with the diaphragm to allow normal flexure of the diaphragm during operation of the engine.

In effecting a priming operation of the engine, the operator first manually moves the plunger 272 upwardly to disengage the spring portions 284 from the recess 276 and engage the spring portions 284 in the circular recess 278. In the upper position with the spring engaged in the recess 278, the diaphragm 92a is moved to open the inlet valve through the lever 117a and arrangement of the character shown in FIGURE 3 preparatory to the operator actuating the squeeze bulb 58 of the priming system to purge the fuel lines of air and effect fuel flow into the fuel chamber 94a.

The inward pressure of the spring or detent portions 284- is sufficient to overcome the biasing pressure of the spring 122, shown in FIGURE 3, to frictionally maintain the fuel inlet valve in open position and the plunger 272 in its uppermost position with the spring in registration with the circumferential groove 278. When the fuel chamber 94a is filled with liquid fuel through the operators actuation of the squeeze bulb 58, shown in FIG- URE 1, fuel pressure is developed in the chamber forcing the diaphragm 92a downwardly to move the plunger 272 downwardly.

This movement disengages the spring portions 284 from the circumferential groove 278 and causes the spring portions 284 to snap into the groove 27 6 to retain the plunger in its out-of-use position during normal engine operation.

Thus, in the forms of the invention illustrated herein, the diaphragm is actuated by a plunger to an uppermost position to open the inlet valve and is held in such valveopening position until fuel flow into the carburetor by manipulation of the squeeze bulb or primer S, develops pressure in the fuel chamber to flex the diaphragm downwardly and restore the diaphragm actuator or plunger to its out-of-use position. Through the use of the method and arrangement of the invention, air in the fuel lines, fuel pump and fuel chamber in the carburetor is exhausted, vented or discharged through the orifices 135, 136 and 158 into the mixing passage, and the small amount of fuel that may flow through the orifices into the mixing passage at the completion of a priming operation is not lost to the atmosphere but will be taken into the engine upon starting the engine. With the arrangement of the invention the operator is immediately informed of the completion of a priming operation by the substantial increased resistance to compression of the squeeze bulb or priming pump 58. Loss of fuel to the atmosphere is prevented and a potential fire hazard eliminated.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. The method of purging air from the fuel supply line connecting a fuel tank with an aspirated type diaphragm carburetor wherein the diaphragm regulates a fuel inlet valve to control fuel flow into a fuel chamber in accordance with the aspiration in the mixing passage of the carburetor including the steps of actuating a movable body from an initial position to move the diaphragm to a position opening the fuel inlet valve, establishing friction on the movable body to releasably maintain the diaphragm in valve opening position, actuating a priming pump connected in the fuel supply line to force any air in the fuel line past the open inlet valve through the fuel chamber into the mixing passage, and thereafter continuing actuation of the priming pump until the fuel chamber is filled with fuel and sufficient fuel pressure established in the fuel chamber to move the diaphragm to close the fuel inlet valve and release the movable body to its initial position away from the diaphragm.

2. The method according to claim 1 wherein the body is manually actuated to move the diaphragm to a position opening the fuel inlet valve.

3. A fuel feed system including a carburetor, a fuel pump arranged to receive liquid fuel from a fuel tank, a manually operable priming pump, tubular means connecting the priming pump with the fuel pump and the fuel tank, duct means for conveying fuel from the fuel pump to the carburetor, said carburetor having a mixing passage and a fuel chamber, a flexible diaphragm forming a wall of the fuel chamber, said fuel chamber being unvented whereby said diaphragm is responsive to aspiration in the mixing passage, a fuel inlet valve in the carburetor, resilient means normally biasing the inlet valve to closed position, means transmitting movements of the diaphragm to the inlet valve to control fuel flow into the fuel chamber in accordance with the aspiration in the mixing passage, passage means in said carburetor for delivering fuel from the fuel chamber to the mixing passage, a member normally out of engagement with the diaphragm, said member being operable to move the diaphragm to open the inlet valve, and friction means engaging said member for retaining the diaphragm in valve-opening position until the fuel chamber is filled with fuel and fuel pressure established in the fuel chamber by manual operation of the priming pump suflicient to move the diaphragm to close the inlet valve and release said member from engagement with the diaphragm.

4. The combination according to claim 3 including a cover for the diaphragm, the member operable to move the diaphragm being a plunger reciprocably mounted in a bore in the cover, and resilient means cooperating with the plunger establishing friction for releasably retaining the diaphragm in valve-opening position when said plunger is actuated to move the diaphragm to open the fuel inlet valve.

5. Charge forming apparatus including, in combination, a body having a mixing passage, an unvented fuel chamber in the body, a fiexible diaphragm forming a wall of the fuel chamber, passage means for conveying liquid fuel from the fuel chamber into the mixing passage, a fuel inlet in the body, a valve for the inlet, tubular means for conveying liquid fuel from a source to the inlet, a priming pump connected with the tubular means for pumping fuel into the fuel chamber, said diaphragm being responsive to aspiration in the mixing passage, means transmitting movement of the diaphragm to the inlet valve to control the position of the inlet valve, resilient means normally biasing the inlet valve toward closed position, a movable member supported adjacent the diaphragm and adapted to be actuated to engage the diaphragm and move the diaphragm to a position opening the inlet valve, and means cooperating with the member for releasably maintaining said diaphragm in valve-opening position, said priming pump being actuable to fill the chamber with fuel and establish sufficient pressure in the fuel chamber effective to move the diaphragm toward inlet valve closing position and release the member from engagement with the diaphragm.

6. The combination according to claim 5 including a cover for the diaphragm, said cover having a bore therein, the diaphragm actuating member being slidably mounted in said bore, said releasable means including a detent engageable with the member effective to retain the member in engagement with the diaphragm, the retaining force of said detent means being of a value to permit retractive movement of said member by the establishment of fuel pressure in the fuel chamber by the priming group.

7. The combination according to claim 5 including a cover for the diaphragm, the cover having a hollow boss, the movable member being a plunger slidably mounted in the hollow boss, said plunger being adapted to be moved to a position engaging and actuating the diaphragm to open the inlet valve to provide fuel flow into the fuel chamber, and friction means for retaining the plunger in diaphragm engaging position, said plunger being released to a retracted position by said diaphragm when the fuel pressure in the fuel chamber established by actuation of the priming pump overcomes the force of the friction means, and a vent for venting the region between the cover and the diaphragm.

8. The combination according to claim 6 wherein the cover is provided with a second bore adjacent the member, the detent being movable in the second bore for engagement with the diaphragm actuating member, and resilient means in'said second bore biasing the detent means into engagement with the member.

9. The combination according to claim 6 wherein the member is a plunger provided with a recess, and spring means disposed in the recess for resiliently retaining the plunger in diaphragm engaging position.

10. The combination according to claim 9 wherein the plunger is fashioned with a peripheral recess, a hairpin spring having portions straddling the plunger, said straddling portions engageable with the recess in the plunger for resiliently retaining the plunger in diaphragm engaging position.

11. The combination according to claim 10 including a tubular eyelet passing through the eye of the hairpin spring and an opening in the cover for securing the hairpin 13 spring to the cover, the tubular eyelet providing a vent opening for the space between the cover and the flexible diaphragm.

References Cited UNITED STATES PATENTS 881,416 3/1908 Krebs 123119XR 1,520,552 12/1924 Adams 123-180 14 Viel 123-119 XR Mock 15836.4 Wirth l23119 XR Phillips 15836.4 Phillips 158-36.4 Barr 123-119 XR LAURENCE GOODRIDGE, Primary Examiner. 

